DNA double-strand breaks (DSB) are considered as the most deleterious DNA lesions, and their repair is further complicated by increasing damage complexity. However, the molecular effects of clustered lesions are yet not fully understood. As the locally restricted phosphorylation of H2AX to form γH2AX is a key step in facilitating efficient DSB repair, we investigated this process after localize...

objective: the itpa gene is responsible to remove free deaminated purine nucleotides of itp, ditp and xtp from nucleotide pool of the cells. it seems that dysfunction in its activity, not only can increas the base substitution mutations frequency but also can works as a contrived factor to creating instability in genetic materials of the cells. there are several reports about the existence of s...

Endogenous and exogenous sources cause free radical-induced DNA damage in living organisms by a variety of mechanisms. The highly reactive hydroxyl radical reacts with the heterocyclic DNA bases and the sugar moiety near or at diffusion-controlled rates. Hydrated electron and H atom also add to the heterocyclic bases. These reactions lead to adduct radicals, further reactions of which yield num...

In cells exposed to ionizing radiation (IR), double-strand breaks (DSBs) form within clustered-damage sites from lesions disrupting the DNA sugar-phosphate backbone. It is commonly assumed that these DSBs form promptly and are immediately detected and processed by the cellular DNA damage response (DDR) apparatus. This assumption is questioned by the observation that after irradiation of naked D...

Heavy particle irradiation produces complex DNA double strand breaks (DSBs) which can arise from primary ionisation events within the particle trajectory. Additionally, secondary electrons, termed delta-electrons, which have a range of distributions can create low linear energy transfer (LET) damage within but also distant from the track. DNA damage by delta-electrons distant from the track has...

use of different pesticides in the agriculture sector, in order to boost crop yield within a short time period and low labor, has been tremendously increased since the last decade. pesticide use has elevated crop yield but has produced a number of pronounced problems regarding environmental and health safety. the continuously deteriorating toxicological effects of these pesticides are not only ...

background: occupational and environmental exposures mostly represent complex mixture of genotoxic agents, however there is a wide variation in the specificity of biomarkers. exploration of correlations among biomarkers contributes to the further progress of molecular cancer epidemiology and to the selection of the optimal biomarkers for the investigation of human exposure to carcinogens. the a...

According to the experimental evidence damage induced by densely ionizing radiation in mammalian cells is distributed along the DNA molecule in the form of clusters. The most critical constituent of DNA damage are double-strand breaks (DSBs) which are formed when the breaks occur in both DNA strands and are directly opposite or separated by only a few base pairs. The paper discusses a model of ...

Apurinic/apyrimidinic sites are the most common forms of DNA damage under physiological conditions, yet their structural and dynamical behavior within nucleosome core particles has just begun to be investigated is dramatically different from that abasic in B-DNA. Clusters two or more repaired even less efficiently hence constitute hot spots high mutagenicity notably due enhanced double-strand b...